package com.calligraphy.order.utils;

import java.lang.reflect.Array;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @Author hy
 * @Date 2019/1/21 11:23
 **/
public class mains {
    public static void main(String[] args) throws Exception {
/*        String str1 = "123";
        String str2 = "123";
        String str3 = new String("123");
        String str4 = new String(str1);
        StringBuilder sb = new StringBuilder("123");
        System.out.println(str1 == str2); //true
        System.out.println(str1 == str3);   //false
        System.out.println(str1 == str4);   //false
        System.out.println(str3 == str4);   //false
        System.out.println(str1.equals(str2));//true
        System.out.println(str1.equals(str3)); //false
        System.out.println(str1.equals(sb.toString()));//true
        System.out.println(sb.equals(str1));    //false
        List<String> l  = new ArrayList<>();
        ((ArrayList<String>) l).trimToSize();*/



    }
}
